Things I liked: Worked fine and had nice instructions. To assemble this item in the gun was a breeze. Improved the strenght an velocity of the shots and the gun shoots like new.

Things I would have changed: Nothing to change

What others should know: My Sniper rifle Type 97 was one of my most accurate snipers and I used to hit the bulls eye at 35 yards all the time using .28 BBs. After installing the upgrade I can only have the same performance using .40 or .43 BBs

Things I liked: It came in my gun. I have reinstalled the original to see the difference it gets about 30fps more with .20grams

Things I would have changed: This uses the standard diameter 11mm outer spring, I would have wanted it to be able to take the larger 13mm uprade springs. If you need to replace this spring it is almost impossable to find something to put in.
after using this for a couple of months, this spring is now 2 inches shorter than it startede.

What others should know: YOU cann't upgrade the spring anymore. Spend the extra money and get an upgrade that will take the better 13mm springs.
Also, upgrade to a metal trigger box.

The spring is definitely the issue. UTG is checking with their engineer to find the maker of the spring used in that kit. Seems wasteful to buy another whole kit just for the fatiguing spring which you don't notice until after the 30 days warranty period!